Last April, in a surprise announcement, Lions Gate, Viacom (Paramount) and MGM announced plans to launch their own, then unnamed, premium cable channel and video on demand service. Soon after, former Showtime executive Mark Greenberg took the helm and the joint venture, dubbed Studio 3 Networks, began to roll toward a planned Q4 2009 launch.

At a TV industry conference in Las Vegas on Tuesday, the company announced Epix will make its broadband debut in May. That will provide at least five months of runway to build brand before the channel’s red carpet introduction as a pay TV channel.

(The time frame to the TV debut is referenced as “at least” because at this point, no cable or satellite distribution (“carriage”) deals have been struck. These discussions are ongoing, and according to sources, they could continue for some time before terms are reached. Until that happens, Epix’ ability to reach consumer TV’s can’t be securely pinned to a fixed date.)

The broadband version of Epix launching in May will have on-demand distribution for Paramount titles released since January 1, 2008 along with United Artists and Lions Gate titles debuting this year.

The list of available features will include recent Oscar nominee, “The Curious Case of Benjamin Button,” hits like Iron Man and classics like the James Bond collection. The online library will total more than 15,000 titles, including TV programs.

Largely in line with “release window” practices, though likely a little faster than some, the on-demand viewing period is expected to begin about nine months after theatrical release.

Mark Greenberg, president of Studio 3 Networks said in a statement that the goal of the venture is flexibility in distribution. “With Epix,” he said, “we are creating an entirely new category of entertainment service for consumers that is unlike anything that currently exists. Epix is the first brand to hold exclusive exhibition rights to movie content that can be delivered anywhere, anytime.”